Principia Mathematica

On hearing that Simon’s “thinking machine” computer program Logic Theorist not only validated Russell and Whitehead’s axioms and theorems (but even proved one more elegantly), Russell replied: “I am delighted to know that Principia Mathematica can now be done by machinery. I [only] wish Whitehead and I had known of this possibility before we both wasted ten years doing it by hand.”

Cited in Herbert A. Simon: The Bounds of Reason in Modern America by Hunter Crowther-Heyck